Reputation: 48387
Is it possible to use the server status variables in a MySQL query?
I can see various metrics from 'show status' but how do I calculate derived values (e.g. the query cache hit ratio)
show global status like 'Qcache_inserts';
show global status like 'Qcache_not_cached';
show global status like 'Qcache_hits';
Ho do I get Qcache_hits/(Qcache_hits+Qcache_inserts+Qcache_not_cached)?
Upvotes: 6
Views: 9253
Reputation: 204934
generally you can access that info due this select:
SELECT
VARIABLE_NAME,
VARIABLE_VALUE
FROM
INFORMATION_SCHEMA.GLOBAL_STATUS
You could make the calculation you want like this:
select (g1.VARIABLE_VALUE / (g1.VARIABLE_VALUE + g2.VARIABLE_VALUE + g3.VARIABLE_VALUE)) as result
FROM INFORMATION_SCHEMA.GLOBAL_STATUS g1
inner join INFORMATION_SCHEMA.GLOBAL_STATUS g2
inner join INFORMATION_SCHEMA.GLOBAL_STATUS g3
where g1.VARIABLE_NAME = 'Qcache_hits'
and g2.VARIABLE_NAME = 'Qcache_inserts'
and g3.VARIABLE_NAME = 'Qcache_not_cached'
Upvotes: 6
Reputation: 3701
Yes you can. Instead of "SHOW STATUS", use "SELECT VARIABLE_VALUE FROM GLOBAL_STATUS" and proceed like any other table.
This table is located in INFORMATION_SCHEMA
database.
Example query :
SELECT VARIABLE_VALUE FROM GLOBAL_STATUS WHERE VARIABLE_NAME="Qcache_inserts"
Hope this helps !
Upvotes: 0